Inbred corn line NP 2017

ABSTRACT

An inbred corn line, designated NP 2017, is disclosed. The invention relates to the seeds of inbred corn line NP 2017, to the plants of inbred corn line NP 2017 and to methods for producing a corn plant produced by crossing inbred line NP 2017 with itself or with another corn plant. The invention further relates to hybrid corn seeds and plants produced by crossing inbred line NP 2017 with another corn line.

BACKGROUND OF THE INVENTION

This invention relates to a new and distinctive corn inbred line designated NP 2017 and to hybrids made by using NP 2017 as a parent.

Corn (Zea mays) is a valuable and important field crop. Thus, plant breeders are continually developing new and superior corn inbred lines for production of high yielding, agronomically sound hybrids. The goal of the plant breeder is to combine in a single variety or hybrid an improved combination of desirable traits from the parent, inbred germplasm. These traits may include maximization of yield, resistance to disease and insects, tolerance to drought, heat and other environmental stresses. These traits are governed by a complex genetic system that makes selection and breeding of an inbred line challenging.

Corn hybrid development requires the development of homozygous inbred lines, the crossing of these lines, and the subsequent evaluation of those crosses. Pedigree, backcross, and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs combine the genetic backgrounds from two or more inbred lines or various other genetic sources into breeding pools from which new inbred lines are developed by self pollination and selection of desired phenotypes. The new inbred lines are crossed with other inbred lines, and hybrids from these crosses are evaluated to determine which have commercial potential.

Once the inbred parents that give a superior hybrid are identified, the hybrid seed can be reproduced indefinitely as long as inbred parent homogeneity is maintained. Corn hybrids may be either single cross hybrids, produced when two inbred lines are crossed to produce the first generation (F1) progeny; double cross hybrids, produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F1 hybrids are crossed again (A×B)×(C×D); or three-way cross hybrids produced from crossing a single cross (A×B) to a third inbred line C. Numerous references are available on the topic of corn breeding and hybrid seed corn production. Those skilled in the art of corn breeding and production are well aware of techniques and methods for the development of inbred corn lines and corn hybrids. However, while many of the techniques and methods are known, breeder care and expertise must be used in the selection of breeding material for resulting yield increase and superior agronomic traits. Reference is made particularly to Corn and Corn Improvement, Third Edition, ed. G. F. Sprague and J. W. Dudley, American Society of Agronomy Monograph No. 18, particularly chapters 8 and 9, the substantive content of which is hereby incorporated by reference.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line, designated NP 2017. This invention thus relates to the seeds of inbred corn line NP 2017, to the plants of inbred corn line NP 2017 and to methods of producing a corn plant comprising the crossing of inbred line NP 2017 with itself or another corn line.

This invention further relates to hybrid corn seed produced by crossing the inbred line NP 2017 with another corn inbred line. More specifically the invention extends to hybrid corn seed produced by planting in pollinating proximity seeds of inbred corn line NP 2017 and a second inbred line having a genotype different from NP 2017; cultivating corn plants resulting from said planting until time of flowering; emasculating the flowers of plants of one of the inbred lines; allowing cross pollination to occur between the inbred lines; and harvesting seeds produced on the plants of the inbred line. The hybrid plants grown from the seed produced as stated above.

DEFINITIONS

In the description and examples that follow a number of terms are used; therefore, to provide a clear and consistent understanding of the specification and claims the following definitions are provided.

RK=Round Kernels: the percentage of kernels that do not pass through a {fraction (13/64)} slotted screen.

HE=Husk Extension: the length (cm) of the husk past the ear tip at maturity.

NN=Node Number: the number of nodes of the entire plant.

PRM=Predicted Relative Maturity. This trait is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks, and is referred to as the Minnesota Relative Rating System.

MST=Harvest Moisture. The moisture is the actual percentage moisture of the grain at harvest.

STK (BR)=The percentage of plants broken below the ear at harvest.

YLD=Yield; bushels per acre. The actual yield of the grain at harvest (bu/a) adjusted to approximately 15.5% moisture.

RT=Number of plants lodged (leaning from vertical but not broken).

Plt. Ht.=Plant Height; The length of the plant to tassel tip (cm).

HU=Heat Units; $\frac{{{Max}\quad {Temp}\quad \left( {\leq {86{^\circ}\quad {F.}}} \right)} + {{Min}\quad {Temp}\quad \left( {\geq {50{^\circ}\quad {F.}}} \right)}}{2} - 50$

HUS=Heat units from emergence to 50% of plants in silk.

HU to pollen=Heat units from emergence to 50% of plants in pollen.

HU to pollen shed=Heat units from 10% to 90% pollen shed.

Ear Ht.=Ear Height. The measurement from the ground to the top developed ear node attachment measured in cm.

DETAILED DESCRIPTION OF THE INVENTION

Inbred corn line NP 2017 is a yellow dent inbred line with superior characteristics and is best suited as a female in crosses for production of first generation (F1) corn hybrids. NP 2017 is best adapted to the North central part of the United States. NP 2017 can be used to produce hybrids from approximately 95 to 105 days relative maturity based on the Minnesota Relative Maturity Rating System for harvest of grain. Inbred line NP 2017 has demonstrated good combining ability with families derived from 0h43 and iodent (for example, W153R) and related lines.

Inbred corn line NP 2017 was derived from the backcross population ((NP 764×H843 1)×H8431)) by selfmg-po ilination and use of standard single pedigree ear-to-row breeding. Line NP 764 (PVP Cert. No. 8700036) and H8431 (PVP Cert. No 8800152) are Northrup King Co. proprietary lines derived from other Northrup King Co. proprietary lines which are derivatives of public inbreds all tracing back to Iowa Stiff Stalk Synthetic. Self-pollination and selection were practiced within the above F1 hybrid cross for seven generations in the development of NP 2017. During the development of the line, crosses of segregating families were made to inbred testers to evaluate combining ability. Inbred line NP 2017 can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollination or sib-pollination conditions with adequate isolation and then harvesting the resulting seed. No variant traits have been observed or are expected in NP 2017.

The inbred line has been evaluated at numerous research stations across the Northern United States Corn Belt and Canada. Inbred line NP 2017 has shown uniformity and stability for all discernible characteristics as described in the following variety description. The description is based on data collected primarily at Stanton, Minn., London, Ontario and Janesville, Wis. on a maximum of 9 replications. In interpreting the color designations herein, reference is made to the Munsell Glossy Book of Color, a standard color reference to describe all color choices. Specific reference is made to

TABLE 1 VARIETY DESCRIPTION INFORMATION FOR INBRED LINE NP 2017, B 68 and H8431 NP 2017 B 68 H8431 Type: Dent Dent Dent Region Best Adapted: North central Northern and Central North central A. Maturity: HU to Silk (HUS): 1180 (63 days) 1561 (77 days) 1237 (65 days) HU to pollen: 1210 (63 days) 1530 (75 days) 1248 (66 days) HU to pollen shed: 84 (4 days) 50 (3 days) 70 (3.5 days) B. Plant Characteristics: Plant height (to tassel tip) (cm): 200 214 200 Length to top ear internode (cm): 13 14 14 Ear height (to base of top ear 76 85 68 internode) (cm): Number of tillers: 0 0 0 Number of ears per stalk: 1.2 1.5 1.3 Cytoplasm type: Normal Normal Normal Anthocyanin of brace roots: Dark Dark Dark C. Leaf: Color: Medium green Dark green Medium green (5GY-4/6) (5GY-4/4) (5GY-4/6 Leaf angle (from 2nd leaf above 45° 58° 52° ear at anthesis to stalk above leaf) Number of leaves- above top ear 6 7 6 (mature plants): Marginal waves: Medium Medium Medium Width (widest point of 9.08 8.55 9.3 ear node leaf) (cm): Sheath Pubescence: Light (1.3) Medium (3) Light (1.3) Longitudinal creases: Medium (6) Medium (6) Medium (7) Length (earnode leaf) (cm): 72.8 88.1 74.0 D. Tassel: Number of primary lateral branches: 8.4 10.3 5.9 Branch angle from central spike: 45° 45° 50° Pollen shed: Medium (5) Medium (5) Medium (5) Anther color: Green-yellow Green-Yellow Green-Yellow (2.5GY-7/6) (2.5GY-7/6) (2.5GY-8/6) Glume color: Medium Green Medium Green Medium Green (5GY-4/8) (5GY-6/8) (5GY-6/8) Bar glumes: absent absent absent E. Ear (Husked ear data except where stated otherwise): Length (cm): 15.9 17.9 16.1 Weight (gm): 120.4 60.3 117.6 Midpoint diameter (mm): 40.7 35.4 40.8 Kernel rows: 13.8 Distinct 13.4 Distinct 13.9 Distinct Straight Slight curve Straight Silk color (3 days after emergence): Purple Green-yellow Purple (5RP-5/10) (2.5GY-8/8) (5RP-5/10) Husk extension: Medium <8 cm Medium <8 cm Medium (<8 cm) Taper of ear: Average Average Average Husk color (fresh) Dark-green Dark-green Medium green 25 days after 50% silking: Husk color (dry) Buff (2.5Y-8/4) Buff (2.5Y-8/4) Buff (2.5Y-8/4) 65 days after 50% silking: Shank length (cm): 6.2 15.3 9.4 F. Kernel (Dried): Size (from ear mid-point): Length (mm): 11.25 8.75 11.84 Width (mm): 8.48 7.75 8.52 Thickness (mm): 4.2 5.00 4.2 Shape grade (% rounds): 42.5 69.25 25.16 Aleurone color: Homozygous Homozygous Homozygous Tan (7.5YR 8/4) Buff (2.5Y 8/4) — Endosperm color: Yellow-orange Yellow-orange Yellow-orange (7.5YR 6/10) (7.5YR 6/10) (7.5YR 8/4) Endosperm type: Normal starch Normal starch Normal starch Gm weight/100 seeds (unsized) 30.4 23.75 27.1 G. Cob: Diameter at mid-point (mm): 21.8 23.0 23.1 Color: Red (10R 4/6) Red (10R 4/6) Red (10R 4/8) H. Agronomic Traits: Stay Green: Medium (5) Good (8) Medium-poor (3) Kg/ha Yield on Inbred per se 3770 3770 (At 12-13% grain moisture) I. Disease Resistance: Eyespot (Kabatiella zeae) 7 7 Northern leaf blight: 5 4 3 Exserohilum turcicum Grey leaf spot: 6 6 6 Cercospora zea-maydis I. Insect Resistance: European Corn Borer (Ostrinia nubilialis) 1st generation 3 3 2nd generation 5 6

The above disease and insect resistance description is based on a scale of 1-9; wherein 1-3 is considered susceptible, 4-5 intermediate, 6-7 resistant and 8-9 highly resistant.

With respect to publicly available inbred lines, NP 2017 most closely resembles B68. However, these lines differ in a number of characteristics. Some of the characteristics between NP 2017 and B68 are summarized in Table 1.

NP 2017 most closely resembles its recurrent parent Northrup King Co. H8431 (PVP Cert. No. 8800152) in terms of usage and maturity, and differs in the characteristics as described in Table 1. The two inbreds have the same silk color, anther color, leaf color, leaf canopy and plant height. Ear height and silking dates are slightly different but not distinctive. However, a number of quantitative traits are statistically differentiating and these include, number of lateral tassel branches, ear shank length, and % round kernals over a {fraction (13/64)} slot.

In addition to phenotypic observations, the genotype of a plant can also be examined. There are many techniques available for the analysis, comparison and characterization of plant genotype and these include isozyme electrophoresis, restriction fragment length polymorphism (RFLPs), randomly amplified polymorphic DNAs (RAPDs) sequence characterized amplified regions (SCARs) and amplified fragment length polymorphisms (AFLPs). While many of the techniques are used, RFLPs have the advantage of revealing an exceptionally high degree of allelic variation in corn. Reference is made to Mumm and Dudley, “A Classification of 148 U.S. Maize Inbreds: I Cluster Analysis based on RFLP's”, Crop Sci 34:842-851 (1994) and Lee, M “Inbred Lines of Maize and Their Molecular Markers” The Maize Handbook (Springer-Verlag, New York, Inc.) 1994 which are hereby incorporated by reference.

Both inbred lines NP 2017 and B68 were subject to various RFLP probes and the results indicate that NP 2017 is identical to B68 for 48 of 99 (59%) of the common RFLP loci. Additional RFLP relationship data indicates that NP 2017 is different from its parent line.

This invention is also directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant, wherein the first or second corn plant is a corn plant of the inbred line NP 2017. However, both first and second parent corn plant can come from the inbred corn line NP 2017. Therefore any methods using NP 2017 are part of this invention including self-pollination, backcross-pollination, hybrid breeding and crosses to populations. It may be desirable to use a male-sterile (either cytoplasmic or nuclear) female parent to prevent self-pollination. If the female is not male-sterile, then either physical or chemical steps may be taken to ensure that self-pollination does not occur. Any plants produced using inbred corn line NP 2017 as a parent are within the scope of this invention including any plant produced by the use of cells, protoplasts or tissue from NP 2017. Specifically NP 2017 produces hybrids that are competitive yielding, and have distinctive red-purple fresh silks three days after silking.

The techniques used to obtain the corn hybrid seeds and plants of this invention are conventional in the seed industry and are well known to those skilled in the art. The two parent lines are planted in pollinating proximity to each other in alternating sets of rows; however, any convenient planting pattern that allows for the free transfer of pollen is acceptable. The plants of both inbred lines are allowed to grow until the time of flowering. At flowering, tassels are removed from all plants of the female parent by hand, machine or other means. Natural cross-pollination is allowed to occur. Ears from the female plants are harvested to obtain novel F1 hybrid corn seeds of the present invention. F1 hybrid corn plants of the invention are obtained by planting seeds harvested from the female plant.

An example of a competitive yielding hybrid of this invention is that produced by the cross Northrup King Co. Inbred line NP 2017×NP 993. Inbred NP 993 is further disclosed in U.S. patent application Ser. No. 08/732,008. The hybrid produced from NP 2017×NP 993 is a 105 Minnesota Relative Maturity (RM) single cross hybrid. This hybrid most closely resembles the commercially available Northrup King Co. hybrid (H8431×NP 993). (H8431×NP 993) is sold in the Northern U.S. and Canada. The hybrid produced by the cross (NP 2017×NP 993) has comparable yield performance to the hybrid produced by the cross H8431×NP 993. In Table 2 below, some of the results are indicated for NP 2017×NP 993 compared to H8431×NP 933 and other similar hybrids. N5220 and N4242 are commercially available Northrup King Co. hybrids. N5220 is made by the cross NP 901×NP 899 (PVP Certificate No.9400106) and is claimed and covered in U.S. Pat. No. 5,530,181. The hybrid produced by the cross (NP 2017×NP 993) has significantly higher yield performance, and slightly higher moisture compared to N4242.

TABLE 2 Combined Location and Year Performance Data (1995, 1996; 42 environments; 95-110 RM Markets) STK YLD (BR) RT Plt Ht Silk Hybrid (bu/a) MST % (cm) HU STBW NP 2017 X NP 993 155 20.9 3.0 0 261 1296 4 H8431 x NP 993 152 20.5 3.0 0 251 1319 5 N4242 147 19.8 3.5 0 261 1292 5 N5220 152 23.4 2.5 1 284 1353 4 P3563 152 23.1 4.0 0 289 1388 8 DK512 151 22.1 3.5 0 270 1348 6 Trails with data: 42 42 LSD 6 0.6 STBW = Stewart's Bacterial Wilt, a rating of 1 = best resistance, 9 = most susceptible.

As used herein the term plant includes plant cells, plant protoplasts, plant cell tissue cultures including that from which corn plants fertile or otherwise can be regenerated, plant calli and plant cell clumps, and differentiated forms of plants such as, but not limited to embryos, pollen, stamen, anthers, flowers, kernels, ears, cobs, leaves, stalks, roots, shoots, plantlets, silks and kernels. In this context, the invention also includes a corn plant regenerated from any NP 2017 corn cell, protoplast and tissue mentioned above and having the same genotype as NP 2017.

Methods of cell and tissue culture and regeneration are well known in the art and described for example in “Plant Tissue Culture Manual: Fundamentals and Application”, Ed. K. Lindsey, Kluwer (1991) and in Green and Rhodes, “Plant Regeneration in Tissue Culture of Maize”, Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va., 1982, pp. 367-372), which are hereby incorporated by reference.

As is well known corn can be put to a wide variety of uses not only as livestock feed but also for human consumption of corn kernels and as a raw material in industry. Both grain and non-grain portions of the plant are used as a livestock feed for swine, cattle and poultry. In the food industry corn is used in wet and dry milling. In wet milling there is the separation of the germ, hull gluten and starch. Germ is used to produce corn oil and germ cake for feed. Corn starch may be packaged for human consumption or used in food products such as sauces, gravies, puddings, sweeteners, syrups, and baking powder. Other nonedible uses include textiles, paper, adhesives, cosmetics, explosives, corn binders, laundry purposes and agricultural formulations. Dry milling is used to produce breakfast foods, grits, cornmeal and corn flour. Other uses of corn include fuel, in the form of fuel alcohol or ethanol; seed; alcoholic beverages and construction.

DEPOSIT INFORMATION

Deposits of at least 2500 seeds of inbred NP 2017, has been made unrestrictedly available to the public via the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA. The deposit corresponds to ATCC Deposit No. 209543, ATCC and was made on Dec. 10 1997. The seeds are from stock maintained by Northrup King since prior to filing this application or any parents thereof. The deposit of inbred corn line NP 2017 will be maintained in the ATCC depository, which is a public depositary, for a period of 30 years, or 5 years after the most recent request, or for the effective life of the patent, whichever, is longer, and will be replaced if it ever becomes nonviable during that period. Additionally, with respect to Plant Variety Protection Certificates received and applied for, Applicant does not waive any infringement of its rights granted under this patent or under the Plant Variety Protection Act (7 U.S.C. 2312 et seq.). 

What is claimed is:
 1. An inbred corn line designated NP 2017, the seeds of which have been deposited as ATCC Accession No.
 209543. 2. Corn plants or parts thereof of inbred corn line designated NP 2017 of claim
 1. 3. A corn plant having all the genetic, physiological and morphological characteristics of the plant of claim
 2. 4. Seeds of the inbred corn line NP 2017 of claim
 1. 5. A tissue culture comprising regenerable cells of the plant according to claim
 2. 6. A corn plant regenerated from the cells or protoplasts of a culture of corn tissue derived from and capable of expressing all the physiological and morphological characteristics of the corn plant of claim
 3. 7. Hybrid seed produced by crossing plants of inbred corn line designated NP 2017, the seed having ATCC Accession No. 209543 and plants of another inbred corn line having a genotype different from corn line NP
 2017. 8. Hybrid seed of claim 7 wherein the corn line NP 2017 is the female parent.
 9. Hybrid corn plants grown from the seed of claim
 7. 10. A tissue culture of regenerable cells of the corn plant of claim
 9. 11. A first generation hybrid corn plant produced by growing hybrid corn seed, wherein said seed is produced by crossing a first inbred parent corn plant with a second inbred parent corn plant wherein said first or second inbred corn plant is the corn plant of claim 2 and harvesting the resultant hybrid seed.
 12. Hybrid corn seed produced by the process of: a. planting in pollinating proximity seeds of inbred corn line NP 2017 having ATCC Accession No. 209543 and a second inbred line having a genotype different from NP 2017; b. cultivating corn plants resulting from said planting until time of flowering; c. emasculating said flowers of plants of said second inbred line; d. allowing cross pollination to occur between said inbreds, and e. harvesting the seeds produced on said plants of inbred line NP
 2017. 13. Hybrid corn plants produced by growing the seeds of claim
 12. 14. A first generation (F₁) hybrid corn plant produced by the process of: a. planting in pollinating proximity seeds of inbred corn line NP 2017 having ATCC Accession No. 209543 and a second inbred line having a genotype different from NP 2017; b. cultivating corn plants resulting from said planting until time of flowering; c. emasculating said flowers of plants of said second inbred line; d. allowing cross pollination to occur between said inbreds; e. harvesting the seeds produced on said plants of inbred line NP 2017 and f. growing a harvested seed of step e.
 15. A corn plant regenerate from the cells or protoplasts of a culture of corn tissue and a genotype capable of expressing all the physiological and morphological characteristics of the corn plant of claim
 14. 